Recovery of phenol from extracts



Oct. 13, 1953 o. MORFIT RECOVERY OF PHENOL FROM EXTRACTS Filed Sept. 30,1949 m 1 RF y Onn M0 w n W 0 N n IR fl Patented Oct. 13, 1953 UNITEDSTATES PATENT OFFICE 2,655,462 RECOVERY or PHENOL FROM EXTRACTS OliverMorfit, Hartsdale, N. Y., assignor to The M. W. Kellogg Company, JerseyCity, N. J., a corporation of Delaware Application September 30, 1949,Serial No. 118,757

2 Claims. (01. 19614.42)

I This invention relates in general to the phenol specificationtreatment of lubricating oils to improve their stantially all of thephenol has been separated vides a method and apparatus for firsteliminatping steam. The steam and phenol vapors from about $250.00 perday, a loss too large to be tol- 45 In the drawing, a stripping tower lis separated erated. into an upper stripping zone 2 and a lower strip-In the method of the present invention the ping zone 3 by means of adraw-01f pan and major portion of the phenol in the extract phasechimney 4. Draw-off pan 4 permits the upward is removed by conventionalprocessing, usually by passage of vapors from lower stripping zone 3 toheating to form a constant boiling mixture and 50 upper stripping zone 2through chimney passage phenol vapor at temperatures of about 250 to andit accumulates liquid as indicated by liqof about 95 per cent oil and 5per cent phenol. stripping zones. The remaining materal will be referredto in this 55 Partially stripped extract phase is charged to anintermediate region of upper stripping zone 2 through an inlet 8 andflows downwardly over the various bubble trays I, encountering vapors asit descends, and being accumulated at level 5 zone 2. A conduit 9 isprovided for continuously withdrawing oil and phenol solution fromdrawofi pan so that all or a portion of said oil may be passed through afurnace i0, preferably with phenol;

phase by hea taining only when it reaches the lower end of upperstripping improved in which meth tacting said and water, and whereinsubstantially all of the phenol and water are separated from saidextract ting to produce an extract oil cona minor percentage of phenol,an thod for recovering residual phenol, od includes: countercurrentlyconextract oil with a hot stripping gas in a first stripping zone tovaporize residual withdrawing extract oil containing the aid Of a pumpit. Heated 011 from furnace i0 10 phenol-0'11 complex not separated fromSaid exis introduced into the upper end i lower stripping zone 3 bymeans of conduit ii. A portion of the oil may by-pass furnace l0 andenter lower tract oil by tract oil to a 650 E2; countercurrentlycontacting said heated gas stripping, and heating said extemperaturebetween 550 F. and

Stripping Zone 3 unheated except by its mixture extract oil in a secondstripping zone with a with hot material from conduit i2, by openingstripping valve it. A flow controlled valve it is provided between pumpH and furnace Hi to maintain a constant liquid flow to the furnace. As aresult of the heating, phenol-oil complexes present in tween 300 F. saidsecond stripping zone an extract oil substantially free of phenol.

2. In the solvent treatment of lubricating oils gas introduced at atemperature beand 500 F.; and recovering from the extract accumulated inthe draw'ofi pang are to increase their viscosity index, which involvesdissociated.

Steam at a temperatureoi 300 F. to 500 F. is charged to the lower end oflower stripping zone 3 through steam inlet l5 at a rate determined bysteam control valve it. As the steam phenol and tract phase containing'0 an improved phenol, which method includes: countercurrently The Steam15 super heated and a contacting said extract oil with a hot strippinggas in a first stripping zone to vaporize residual withdrawingphenol-oil complex not separated from said extract oil by gas stripping,and heating said extract The phenol vapor and steam on to a tempe passesupwardly through lower stripping zone 3 and encounters the down flowingliquid therein, residual phenol resulting from the breaking up of thephenol-oil complexes is stripped away from the liquid. vapor mixture ofsteam and phenol having a temperature of about 500 F. passes upwardlythrough lower tray passage 5 into the lower end of upper stripping zone2 wherein it serves as stripping vapor. mixture is withdrawn throughline ii at the upper end of tower l.

Extract oil, substantially free of phenol accumulates in the lower endof lower stripping zone phenol;

contacting oil with phenol to obtain a raffinate phase of improvedviscosity index, and an extract phase comprised exclusively of extractoil, phenol, and water, and wherein substantially all of the water areseparated from said exby heating to produce an extract on nly a minorpercentage of phenol,

method for recovering residual extract oil containing rature between 550F. and 650 F.;

countercurrently contacting said heated extract oil in a secondstripping zone with a stripping gas introduced at a temperature between300 F. and 500 F.; passing said stripping gas, heated in 3 and isWithdrawn through line by means of 40 said second stripping zone by saidcountercurpump it at a rate controlled by valve 20 operated by means ofliquid level controller 2 l.

Preferably, phenol is returned to the upper end of upper stripping zone2 through a reflux line 22. Within lower stripping zone 3, temperaturesof rent contact upwardly through said first stripping zone; withdrawingvaporized residual phenol and stripping second stripping zone andrecovering said phenol;

and recovering from said second stripping zone gases from the upper endof said the liquid range from about 550 F. at the lower an extract onSubstantially free of phenoL end to about 650 F. at the upper end, whilevapor temperature ranges at about 600 F. at the upper end. In upperstripping zone 2 temperatures of both llquid and vapor are about 500 F.throughout except above the inlet where the reflux lowers the vaportemperature to 300 to 400 F. Number I claim; 2,052,196 1. In the solventtreatment of lubricating oils 2,034,471 to increase their viscosityindex, which involves 2,120,310 contacting oil with phenol to obtain araiiinate 2,216,933 phase of improved viscosity index, and an extract2,357,710 phase comprised exclusively of extract oil, phenol, ,809

OLIVER MO-RFIT.

References Cited in the file of this patent UNITED STATES PATENTS NameDate Stratiord Aug. 25, 1936 Whiteley June 22, 1937 Parkhurst June 14,1938 Atkins Oct. 8, i940 Ullrich Sept. 5, 1944 Rup et al. Nov. 26, 1946

1. IN THE SOLVENT TREATMENT OF LUBRICATING OILS TO INCREASE THEIR VISCOSITY INDEX, WHICH INVOLVES CONTACTING OIL WITH PHENOL TO OBTAIN A RAFFINATE PHASE OF IMPROVED VISCOSITY INDEX, AND AN EXTRACT PHASE COMPRISED EXCLUSIVELY OF EXTRACT OIL, PHENOL, AND WATER, AND WHEREIN SUBSTANTIALLY ALL OF THE PHENOL AND WATER ARE SEPARATED FROM SAID EXTRACT PHASE BY HEATING TO PRODUCE AN EXTRACT OIL CONTAINING ONLY A MINOR PERCENTAGE OF PHENOL, AN IMPROVED METHOD FOR RECOVERING RESIDUAL PHENOL, WHICH METHOD INCLUDES: COUNTERCURRENTLY CONTACTING SAID EXTRACT OIL WITH A HOT STRIPPING GAS 